Endocrine activity of the postmenopausal ovary: the effects of pituitary down-regulation and oophorectomy

Abstract

The endocrine activity of the postmenopausal ovary and the effect of pituitary down-regulation were studied in a group of 35 postmenopausal women. All women underwent oophorectomy with or without hysterectomy. Fifteen women received a single dose of a depot GnRH agonist (GnRHa) 2 weeks before operation, whereas 20 women formed the control group. Peripheral venous levels of LH, FSH, estrone, 17 beta-estradiol, testosterone (T), androstenedione (A), sex hormone-binding globulin, and dehydroepiandrosterone sulfate were measured 2 weeks before, during, and 6 weeks after surgery. Ovarian venous blood was sampled during surgery. In the GnRHa and control groups, ovarian venous levels of A and T were significantly higher, and those of dehydroepiandrosterone sulfate and sex hormone-binding globulin significantly lower, compared to the peripheral levels. A significant decrease in T was found in the peripheral and ovarian vein samples during pituitary down-regulation with GnRHa. Six weeks after operation, peripheral T levels were significantly lower than those during surgery in the group that was down-regulated at the time of oophorectomy. We conclude that the postmenopausal ovary produces significant amounts of A and T, although only T contributes significantly to its peripheral serum levels. T production by the postmenopausal ovary is in part stimulated by the high levels of circulating gonadotropins, although pituitary down-regulation does not completely abolish androgenic activity.

Preservação da fertilidade e dos ovários em mulheres com tumores anexiais benignos

“…A ooforectomia cirúrgica, tanto na pré quanto na pós-menopausa, está relacionada a riscos mais elevados de doenças cardiovasculares, osteoporose, fraturas de quadril, demência, doença de Parkinson, depressão, ansiedade e disfunção sexual, segundo revisão realizada por Parker em 2010 16 . Mesmo após a menopausa, o ovário continua a produzir androstenediona e testosterona que são convertidos em estrona no tecido adiposo periférico, músculo e pele 17 . Apesar do estudo de Parker et al 18 baseado no modelo analítico de Markov demonstrar maior mortalidade e morbidade após ooforectomia em mulheres com menos de 65 anos, a recomendação da American College of Obstetricians and Gynecologists (ACOG) de 2008 19 sugere que a menopausa seja o fator determinante para ooforectomia no momento da histerectomia.…”

Postmenopausal serum androgens, oestrogens and breast cancer risk: the European prospective investigation into cancer and nutrition

“…Although the ovaries are the predominant glandular source of circulating testosterone, only about 40% of circulating testosterone comes from ovaries, and most of the remainder is formed by extraglandular conversion of androgenic precursors (Longcope 1986, Adashi 1994. Although bilateral ovariectomy has been found to mildly reduce circulating androgen levels, especially androstenedione and testosterone, in postmenopausal women (Sluijmer et al 1995, Kenemans & Bosman 2003, ovariectomy after the age of 45-50 years does not appear to decrease breast cancer risk (Schairer et al 1997, Kreiger et al 1999.…”

Exploring Breast Cancer Estrogen Disposition: The Basis for Endocrine Manipulation

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